1. Field of the Invention
The present invention relates to a cassette accommodating an object which needs to be electrically connected to the outside.
2. Description of the Related Art
Japanese patent laid-open No. 79234/1984 discloses a cassette in which a roll of electrophotographic film in the shape of a tape is accommodated in a cassette casing.
Electrophotographic film, when applied to, for example, a document storage and retrieval system, provides various advantages which cannot practically be obtained from conventional films made of a silver halide photosensitive material, as is described in the specification of Japanese patent laid-open No. 79234/1984. Electrophotographic film is expected to become more practically utilizable by accommodating it in a cassette which will facilitate its management, storage and handling.
This electrophotographic film is formed from a transparent base in the shape of a tape which includes, for example, polyester as its principal component, together with a transparent electrically conductive layer and a transparent photoconductive insulating layer which are, in that order, coated on the base, the electrically conductive layer needing to be grounded when, for example, it is electrically charged. Accordingly, the electrically conductive layer of such electrophotographic film is grounded by some appropriate means, and it may be considered reasonable to assume that, when electrophotographic film is accommodated in a cassette, an external contact which is electrically connected to the electrically conductive layer is disposed on the outer surface of the cassette casing. When the cassette is loaded in an electrophotographic recording apparatus, the external contact may be electrically connected to a contact which is disposed on this apparatus so that the electrically conductive layer is grounded.
If this grounding is incompletely effected, it is not possible to record an excellent image on the electrophotographic film, and it may lead to a failure in recording. More specifically, when foreign matter such as dust is attached to the external contact of the cassette or the contact on the apparatus into which the cassette is loaded, or when an oxide film or sulfide film is formed on such contact, the two contacts easily cause a contact failure. Any contact failure may lead to a problem such as fogging of the recorded image.